Novel aryl carbonate cyanoaryl ether gas separation membranes

Abstract

The invention relates to novel aryl carbonate cyanoaryl ether gas separation membranes and a method of separating gases using such membranes.

What is claimed is: 
     
       1. A semi-permeable gas separation membrane comprising a thin discriminating layer of an uncross-linked or cross-linked aryl carbonate cyanoaryl ether copolymer possessing a polymer backbone structure corresponding to the formula: ##STR6## wherein Ar 1  and Ar 2  are each individually a divalent aromatic residue selected from the group consisting of: A. an unsubstituted or inertly substituted phenylene, unsubstituted or inertly substituted naphthylene;   B. ##STR7##  wherein L is selected from the group consisting of a direct bond, a divalent C 1-15  hydrocarbyl radical, a divalent C 1-8  halohydrocarbyl radical, --O--, --CO--, --S--, --SO--, --SO 2  --, and --SS--, X is individually in each occurrence selected from the group consisting of a hydrogen radical, a monovalent C 1-4  hydrocarbyl radical, a C 1-4  halohydrocarbyl radical, and a halogen, and   m is an integer between 1 and 4 inclusive; and     C. a divalent bisphenyl fluorenyl or spiro indanyl radical; R is individually in each occurrence selected from the group consisting of a hydrogen radical, a monovalent C 1-4  hydrocarbyl radical, a C 1-4  halohydrocarbyl radical, and a halogen, and   q is a positive integer between 1 and 3 inclusive;   s is a positive integer between about 1 and about 250 inclusive   x is a positive integer between about 0 and about 250 inclusive, and   y is a positive integer between about 1 and about 500 inclusive,      wherein the ratio of y/(x+y) is between about 0.25 and 1 inclusive: and   n is a positive integer representing a degree of polymerization which provides a number-average molecular weight of at least about 4,000.     
     
     
       2. The membrane of claim 1 wherein Ar 1  and/or Ar 2  comprise an inertly substituted phenylene or naphthylene, wherein the inert substituents are selected from the group consisting of a monovalent C 1-8  hydrocarbyl radical, a monovalent C 1-8  hydrocarbyloxy radical, and a halogen. 
     
     
       3. The membrane of claim 2 wherein the inert substituents are selected from the group consisting of a monovalent C 1-4  hydrocarbyl radical, a monovalent C 1-4  hydrocarbyloxy radical, and a halogen. 
     
     
       4. The membrane of claim 3 wherein the inert substituents comprise a halogen selected from the group consisting of fluorine, chlorine, and bromine. 
     
     
       5. The membrane of claim 1 wherein Ar 1  and/or Ar 2  comprise ##STR8## wherein L is selected from the group consisting of a direct bond, a divalent C 1-8  hydrocarbyl radical, a divalent C 1-4  halohydrocarbyl radical, --O--, --CO--, --S--, --SO--, --SO 2  --, and --SS--. 
     
     
       6. The membrane of claim 5 wherein L is selected from the group consisting of a direct bond, a divalent C 1-4  hydrocarbyl radical, a divalent C 1-4  halohydrocarbyl radical, --O--, --CO--, --S--, --SO--, --SO 2  --, and --SS--. 
     
     
       7. The membrane of claim 6 wherein L is selected from the group consisting of a direct bond, a divalent C 1-3  hydrocarbyl radical, and a divalent C 1-3  fluorohydrocarbyl radical. 
     
     
       8. The membrane of claim 7 wherein L is selected from the group consisting of a direct bond, an unsubstituted or fluoro-substituted methylene radical, and an unsubstituted or fluoro-substituted isopropylidene radical. 
     
     
       9. The membrane of claim 1 wherein Ar 1  and/or Ar 2  comprise ##STR9## wherein X is selected from the group consisting of a hydrogen radical, a monovalent C 1-3  hydrocarbyl radical, a monovalent C 1-3  halohydrocarbyl radical, and a halogen. 
     
     
       10. The membrane of claim 9 wherein X is selected from the group consisting of a fluorohydrocarbyl radical and fluorine. 
     
     
       11. The membrane of claim 1 wherein the membrane is composite or asymmetric. 
     
     
       12. The membrane of claim 1 wherein the membrane is a hollow fiber. 
     
     
       13. The membrane of claim 1 wherein the separation factor for helium/methane at about 30° C. is at least about 35. 
     
     
       14. The membrane of claim 1 wherein the separation factor for helium/ethane at about 30° C. is at least about 75. 
     
     
       15. The membrane of claim 1 wherein the separation factor for helium/ethylene at about 30° C. is at least about 25. 
     
     
       16. The membrane of claim 1 wherein the permeability for helium is at least about 9 Barrers. 
     
     
       17. The membrane of claim 1 wherein the separation factor for oxygen/nitrogen at about 30° C. is at least about 4.5. 
     
     
       18. The membrane of claim 1 wherein the permeability for oxygen is at least about 0.5 Barrers. 
     
     
       19. The membrane of claim 1 wherein the copolymer is cross-linked by reaction with a polyepoxide compound. 
     
     
       20. The membrane of claim 19 wherein the separation factor for helium/methane at about 30° C. is at least about 80. 
     
     
       21. The membrane of claim 19 wherein the separation factor for helium/ethane at about 30° C. is at least about 250. 
     
     
       22. The membrane of claim 19 wherein the separation factor for helium/ethylene at about 30° C. is at least about 35.